Field intensity: An 800-kHz radio signal is detected at a point 9.1 km distant from a transmitter tower. The electric field amplitude of the signal at that point is 0.440 V/m. Assume that the signal power is radiated uniformly in all directions and that radio waves incident upon the ground are completely absorbed. What is the average total power radiated by the transmitter? (c = 3.00 × 10⁸ m/s, μ₀ = 4π × 10^-7 T ∙ m/A, ε₀ = 8.85 × 10^-12 C²/N ∙ m²) A) 0.27 MW B) 0.32 MW C) 0.38 MW D) 0.45 MW E) 0.50 MW

Question

Quizplus · Accepted Answer

The correct answer is A because the average total power radiated by the transmitter is 0.27 MW. This can be calculated using the formula P = (1/2)ε0cE2A, where P is the power, ε0 is the permittivity of free space, c is the speed of light, E is the electric field amplitude, and A is the area of the sphere surrounding the transmitter.

Field Intensity: an 800-KHz Radio Signal Is Detected at a Point